Solar Cells Research Articles

Asymmetrified Benzothiadiazole-Based Solid Additives Enable All-Polymer Solar Cells with Efficiency Over 19 .

Disordered polymer chain entanglements within all-polymer blends limit the formation of optimal donor-acceptor phase separation. Therefore, developing effective methods to regulate morphology evolution is crucial for achieving optimal morphological features in all-polymer organic solar cells (APSCs). In this study, two isomers, 4,5-difluorobenzo-c-1,2,5-thiadiazole (SF-1) and 5,6-difluorobenzo-c-1,2,5-thiadiazole (SF-2), were designed as solid additives based on the widely-used electron-deficient benzothiadiazole unit in nonfullerene acceptors. The incorporation of SF-1 or SF-2 into PM6 : PY-DT blend induces stronger molecular packing via molecular interaction, leading to the formation of continuous interpenetrated networks with suitable phase-separation and vertical distribution. Furthermore, after treatment with SF-1 and SF-2, the exciton diffusion lengths for PY-DT films are extended to over 40 nm, favoring exciton diffusion and charge transport. The asymmetrical SF-2, characterized by an enhanced dipole moment, increases the power conversion efficiency (PCE) of PM6 : PY-DT-based device to 18.83 % due to stronger electrostatic interactions. Moreover, a ternary device strategy boosts the PCE of SF-2-treated APSC to over 19 %. This work not only demonstrates one of the best performances of APSCs but also offers an effective approach to manipulate the morphology of all-polymer blends using rational-designed solid additives.

Enhanced Absorption in SnS/SnSe, SnS/ZnS, and SnS/ZnSe vdW Heterostructures for Optoelectronic Applications: DFT Insights

Abstract The electronic and optical properties of monolayers of tin monochalcogenides and zinc monochalcogenides are elucidated by utilizing density functional theory. The calculated results indicate that the monolayers of tin monochalcogenides (SnS and SnSe) have low bandgap and significant absorption in some segments of the visible region (~400 nm to ~500 nm). However, the monolayers of zinc monochalcogenides (ZnS and ZnSe) have wide bandgap and negligible absorption in the visible region, which limits their optical performance. Despite low absorption in visible region, ZnS and ZnSe exhibit fascinating properties such as wide band gap, cheapness, low toxicity, earth abundance, structural stability, and high refractive index. To identify the combined potential of zinc and tin, the van der Waals heterostructures SnS/SnSe, SnS/ZnS, and SnS/ZnSe are formed, and their optical and electronic properties are calculated. The calculated results illustrate that the formed heterostructures exhibit bandgap lowering and enhanced visible light absorption. The optical absorption is entirely shifted towards the visible region due to the formation of heterostructure (redshift). The enhanced visible light absorption and narrowed bandgap of the formed heterostructures make them a potential candidate for the fabrication of optoelectronic devices and solar cells.

Magnetron sputtered silicon thin films for solar cell applications

One of the important directions of research in photovoltaics is the development of new thin-film technology, which can replace the currently used, more expensive bulk silicon technology. The article discusses the findings from research focused on optimizing the parameters for the deposition of silicon thin films with P-type electrical conductivity for applications in photovoltaics. The growth rate was determined depending on the change in substrate temperature using reflectometry and the influence of deposition time on optical properties was determined using UV/VIS spectroscopy. Photovoltaic structures were made on substrates with an ITO layer and their electrical parameters were measured. The authors applied the magnetron sputtering method to deposit the layers, selecting it over the commercially used the chemical vapor deposition (CVD) method. This replacement could alleviate the necessity for high temperatures and broaden the potential applications of thin-film solar cells.

Innovative Approaches to Large-Area Perovskite Solar Cell Fabrication Using Slit Coating.

Perovskite solar cells (PSCs) are gaining prominence in the photovoltaic industry due to their exceptional photoelectric performance and low manufacturing costs, achieving a significant power conversion efficiency of 26.4%, which closely rivals that of silicon solar cells. Despite substantial advancements, the effective area of high-efficiency PSCs is typically limited to about 0.1 cm2 in laboratory settings, with efficiency decreasing as the area increases. The limitation poses a major obstacle to commercialization, as large-area, high-quality perovskite films are crucial for commercial applications. This paper reviews current techniques for producing large-area perovskites, focusing on slot-die coating, a method that has attracted attention for its revolutionary potential in PSC manufacturing. Slot-die coating allows for precise control over film thickness and is compatible with roll-to-roll systems, making it suitable for large-scale applications. The paper systematically outlines the characteristics of slot-die coating, along with its advantages and disadvantages in commercial applications, suggests corresponding optimization strategies, and discusses future development directions to enhance the scalability and efficiency of PSCs, paving the way for broader commercial deployment.

Optimization of monocrystalline silicon solar cell using Box–Behnken design and machine learning models

Optimization of monocrystalline silicon solar cell using Box–Behnken design and machine learning models

Dopant-Free Hole Transport Material Based on Non-Covalent Interaction for Efficient Perovskite Solar Cells.

Hole transport materials (HTMs) have a critical impact on the performance of perovskite solar cells (PSCs). Especially, the dopant-free HTMs could avoid the usage of hygroscopic dopants and reduce costs, which are important for device stability. Most of the current organic dopant-free HTMs are polycyclic aromatic hydrocarbons-based planar conjugated structures. Yet, the synthesis of conjugated fused heterocycles is often complicated. In this work, intramolecular non-covalent interaction is introduced to construct two organic HTMs (DCT and DTC), which can be facilely obtained through simple reactions. Compared to DTC with hexyl chain on the central benzene ring, DCT with hexyloxy chains shows better planarity in the core structure, as a result of the intramolecular non-covalent interactions between oxygen on hexyloxy and sulfur atom on the adjacent thiophene, as reflected from its single crystal structure. Moreover, DCT in a pristine state shows a decent hole mobility comparable to the doped Spiro-OMeTAD. Ultimately, conventional devices using dopant-free DCT as HTM show a high efficiency of 22.50%, with excellent long-term stability, and light and thermal stability. The results show that the noncovalent interaction is a useful and simple design strategy for dopant-free HTMs, that can effectively improve the efficiency and stability of PSCs.

Sustainable Molecular Passivation via Heat-Induced Disaggregation and Redox Reactions for Inverted Perovskite Solar Cells

Sustainable Molecular Passivation via Heat-Induced Disaggregation and Redox Reactions for Inverted Perovskite Solar Cells

Device optimization of all-perovskite triple-junction solar cells for realistic irradiation conditions

Device optimization of all-perovskite triple-junction solar cells for realistic irradiation conditions

Structure and Properties of Thin Films Prepared on Flexible Substrates from SnCl4-Derived Solutions

Thin transparent films of SnO2 were obtained from aqueous–alcohol solutions of SnCl4 on a flexible polyethylene terephthalate (PET) substrate by spray pyrolysis at 100 °C. The influence of the addition of aqueous ammonia to the film-forming solution on the different properties has been studied. Properties studied include surface morphology, phase composition and transparency of the formed films and the crystallization processes and band gap of the film material. It was found that the addition of aqueous ammonia causes the formation of skeletal crystals (NH4)2[SnCl6] with a perovskite structure in the film structure. The resulting films are promising for use in the technology of manufacturing flexible solar cells.

Multidentate Polymer-Stabilized Buried Interface for Efficient Planar Perovskite Solar Cells.

Buried interface engineering is crucial to improve the performance and stability of perovskite solar cells (PSCs). Although coordination materials have been widely used for buried interface modification, they are generally engineered on one surface of the interface through monodentate or bidentate molecules. Here, we propose that a multidentate polymer, sodium alginate (SA), acts with both surfaces via numerous C═O groups to reinforce buried interfaces. SA effectively reduces buried interface defects, adjusts the energy level alignment, and refines carrier dynamics. Notably, it also induces the growth of a perovskite film that is less tensile stressed and free of voids. Consequently, the champion device efficiency after SA treatment increased from 23.05% to 24.98%, along with significant improvements in both light and thermal stability. This work offers insights into efficiency and stability improvement from the perspective of multidentate polymer anchoring.

A Diphosphonic Acid-Based Interlayer for Highly Efficient and Stable Inverted Perovskite Solar Cells.

We investigate an interlayer of 6,6'-bis(4-(bis(4-methoxyphenyl)amino)phenyl)-[1,1'-binaphthalene]-(2,2'-diyl)bis(oxy)bis(propane-3,1-diyl)bis(phosphonic acid) (BINOL-PA) with undoped poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) coverage. The incorporation of the 1,10-bi-2-naphthol central core enhances π-π stacking and reduces charge recombination at the interface. Compared to PTAA alone (0.95 eV), BINOL-PA/PTAA exhibits a shorter distance from the Fermi energy (EF) to the valence-band maximum (VBM) (0.36 eV). Two phosphoric acid units in BINOL-PA fine-tune the molecular dipoles. Theoretical calculations reveal electrostatic surface potential differences between BINOL-PA and PTAA in their backbone structure. Open-circuit voltage decay (OCVD) and electrochemical impedance spectroscopy (EIS) results suggest suppressed interface recombination. The photovoltaic conversion efficiency (PCE), short-circuit current density (JSC), open-circuit voltage (VOC), and fill factor (FF) for the BINOL-PA/PTAA device are measured as 21.02%, 22.67 mA cm-2, 1.12 V, and 82.8%, respectively, all higher than those achieved by the PTAA device with a PCE of 18%. BINOL-PA/PTAA significantly elevates VOC and FF values compared with dopant-free PTAA alone. The champion device retains over 89% of its initial PCE after being exposed to an ambient environment without encapsulation for more than 30 days. The thermal aging test conducted under a nitrogen atmosphere demonstrates that the efficiency retention rate for BINOL-PA/PTAA displays 60% of its initial efficiency after 1500 h.

Humidity Resistance of Inverted Perovskite Solar Cells as Measured by Operando X-ray Scattering

Humidity Resistance of Inverted Perovskite Solar Cells as Measured by Operando X-ray Scattering

Bottom-Up Formation of III-Nitride Nanowires: Past, Present, and Future for Photonic Devices.

The realization of semiconductor heterostructures marks a significant advancement beyond silicon technology, driving progress in high-performance optoelectronics and photonics, including high-brightness light emitters, optical communication,and quantum technologies. In less than a decade since 1997, nanowires research has expanded into new application-driven areas,highlighting a significant shift toward more challenging and exploratory research avenues. It is therefore essential to reflecton the past motivations for nanowires development, and explorethe new opportunities it can enable. The advancement of heterogeneous integration using dissimilar substrates, materials, and nanowires-semiconductor/electrolyte operating platforms is ushering in new research frontiers, including the development of perovskite-embedded solar cells, photoelectrochemical (PEC) analog and digital photonic systems, such as PEC-basedphotodetectors and logic circuits, as well as quantum elements, such assingle-photon emitters and detectors. This review offersrejuvenating perspectives on the progress of these group-III nitride nanowires,aiming to highlight the continuity of research toward high impact, use-inspired researchdirections in photonics and optoelectronics.

Efficient and Scalable Radiative Cooling for Photovoltaics Using Solution‐Processable and Solar‐Transparent Mesoporous Nanoparticles

AbstractContinuous heat generation in perovskite solar cells (PSCs), caused by solar radiation, poses a significant challenge to their lifespan. Existing active cooling methods require extra energy input and might not be effective at high temperatures. Most reported passive radiative cooling materials either lack solar transparency or require complex fabrication processes. Here, mesoporous silica nanoparticles are designed, synthesized, and assembled into multilayered stacks with a graded refractive index (GRI) by spray coating them on top of PSCs made from methylammonium lead iodide (MAPbI3) over a large scale (15.6 × 15.6 cm2). This coating offers both high transparency in the visible wavelength and high emissivity in the mid‐infrared region, leading to an average temperature reduction of 6.65 ± 1.48 °C in GRI‐coated MAPbI3 PSCs under outdoor conditions compared to non‐coated references. After 50 d, the GRI‐coated PSCs maintain 80.9 ± 8.7% of their initial photoconversion efficiency, in contrast to 6.1 ± 5.9% for the noncoated ones. The calculated cooling power of the GRI‐coated PSCs is 28.9% higher than that of the reference cells.

Photoelectrochemical Hydrogen Production from Water Using Copper‐based Chalcopyrite Thin Films

AbstractCopper (Cu)‐based chalcopyrite compounds are promising photoabsorber materials not only for solar cells but also for photoelectrochemical (PEC) systems for conversion of sunlight energy into chemical energy. PEC water splitting to generate hydrogen (H2) is one of the most advanced technologies in a PEC system for the use of Cu‐based chalcopyrite compounds. In this review, we firstly introduce crystallographic/energetic structures of Cu‐based chalcopyrite compounds in view of their applications to PEC water splitting. Explanations for the operation of PEC water splitting using semiconductor materials are then overviewed. Based on these backgrounds, studies on PEC H2 evolution over photocathodes based on CuInS2 and CuGaSe2 thin films that we have developed are reviewed in detail. For realizing efficient PEC H2 evolution over these thin films, surface modifications with an n‐type layer such as CdS and a catalytic site such as Pt deposit were found to be indispensable. Precise controls of p‐n heterointerfaces formed by introducing an n‐type layer should also be required to enhance PEC performance. Although PEC water splitting has not reached the required efficiency to be useful, effective combinations of appropriate surface and interface modifications should lead to further improvements of properties to be close to practical applications.

Visible-light-driven Fe-catalyzed alkylation for synthesizing functionalized polyolefin elastomers as advanced encapsulants in photovoltaic modules

Polyolefin elastomer (POE) has emerged as a promising encapsulant for photovoltaic modules, attributed to its exceptional water vapor barrier properties, robust weather resistance, and enhanced anti-potential induced degradation (anti-PID) capabilities. Despite these advantages, the interfacial adhesion of POE remains a significant challenge, particularly its suboptimal bonding with glass and solar cells, which impedes its broader application within the photovoltaic industry. This study introduced glycidyl methacrylate (GMA) monomers into POE through a photo-induced iron-catalyzed alkylation reaction, developing a novel polyolefin encapsulant for photovoltaic modules. The encapsulant was designed to possess high light transmittance, enhanced adhesion, and elevated resistivity. The modified POE boasts an impressive light transmittance nearing 98% and an adhesive strength of 28.3 N cm−1, both superior to traditional ethylene-vinyl acetate copolymer (EVA) materials. Additionally, this work delves into the correlation between crystallization behavior and light transmittance, elucidating the influence of GMA incorporation on the adhesion and insulation properties of POE through gaussian simulations.

Researching Organic Solar Cells from the Perspective of Literature Big Data Analysis

Solar cell research aims to improve power conversion efficiency (PCE). This field has an extensive body of literature on the Web of Science. For researchers, it is impossible to understand the development of the entire field comprehensively through traditional reading methods. Knowledge is recorded in the literature by text and numbers. Researchers acquire knowledge through literature surveying, text reading, and thinking. The conversion from text and numbers to knowledge can be automatically completed by machines, which can avoid path‐dependent perspectives. In this work, an intelligent machine learning method for literature structure delineation and information extraction is proposed. As an example, a knowledge base of organic solar cells (OSCs) is extracted including topic analysis of literature, numerical characteristics of performance, and material information. Seven major research directions of OSCs are identified. The correlations between key performance parameters, including PCE, short‐circuit current density (JSC), open‐circuit voltage (VOC), and fill factor (FF), are revealed from text mining. A donor–acceptor material map of PCE is constructed which provides a road map for OSCs, indicating the bottleneck of this field. Moreover, the method of machine intelligence developed here can be used in any other materials field, aiding a comprehensive understanding of the development quickly.

Enhanced Photovoltaic Performance of Poly(3,4-Ethylenedioxythiophene)Poly(N-Alkylcarbazole) Copolymer-Based Counter Electrode in Dye-Sensitized Solar Cells

Conducting polymers are emerging as promising alternatives to rare and expensive platinum for counter electrodes in dye-sensitized solar cells; due to their ease of synthesis, they can be chemically tuned and are suitable for roll-to-roll production. Among these, poly (3,4-ethylenedioxythiophene) (PEDOT)-based counter electrodes have shown leading photovoltaic performance. However, certain conductivity issues remain that affect the effectiveness of these counter electrodes. In this study, we present an electropolymerized PEDOT and poly(N-alkylated-carbazole) copolymer as an efficient electrocatalyst for the reduction in I3− in dye-sensitized solar cells. Copolymerization with N-alkylated carbazoles significantly increases the conductivity of the polymer film and facilitates rapid charge transport at the interface between the polymer electrode and the electrolyte. The length of the alkyl substituents also plays a crucial role in this improvement. Electrochemical analysis showed a reduction in charge transport resistance from 3.31 Ω·cm2 for PEDOT to 2.26 Ω·cm2 for the PEDOT:poly(N-octylcarbazole) copolymer, which is almost half the resistance of a platinum-based counter electrode (4.12 Ω·cm2). Photovoltaic measurements showed that the solar cell with the PEDOT:poly(N-octylcarbazole) counter electrode achieved an efficiency of 8.88%, outperforming both PEDOT (7.90%) and platinum-based devices (7.57%).

Charge Carrier Dynamics of SnO2 Electron‐Transporting Layers in Perovskite Solar Cells

Perovskite solar cells (PSCs) have demonstrated remarkable increase in their photovoltaic efficiencies over the past several years. Charge carrier properties including charge selectivity, extraction, and transport play key roles in device performances. Therefore, a comprehensive insight into the charge carrier dynamics and mobility within the bulk materials and at the interface is of great importance for the future development of this cutting‐edge technology. This review discusses the recent advances that have been made in SnO2 electron‐transporting layers and their limitations, followed by outlining the key development of novel strategies in improving SnO2 films through surface defect engineering, interface modification, and doping approaches. In addition, the recent developments are highlighted for identifying the origin of defect and trap center, and promoting SnO2 electron extraction and transporting capacity in PSCs. Importantly, the novel approaches are also discussed for studying photogenerated charge carrier dynamics of the devices. In conclusion, the own prospectives and outlooks are presented for the development of SnO2‐based PSCs, with a particular focus on addressing current difficulties in SnO2 and providing in‐depth understanding on the relationships between materials and devices.

Morphology Optimization by Non-Halogenated and Twisted Volatile Solid Additive for High-Efficiency Organic Solar Cells.

Recently, volatile solid additives have attracted tremendous interest in the field of organic solar cells (OSCs), which can effectively improve device efficiency without sacrificing the reproducibility and stability of the device. However, the structure of reported solid additives is onefold and its working mechanism needs to be further investigated. Herein, a novel non-halogenated and twisted solid additive 1,4-diphenoxybenzene (DPB) is employed to optimize the morphology of the active layer in OSCs. The properties of additive DPB, morphology of active layer, and carrier dynamics behaviors have been systematically investigated through theoretical calculations, in situ and ex situ spectroscopy, grazing-incidence wide-angle X-ray scattering (GIWAXS), and grazing-incidence small-angle X-ray scattering (GISAXS) measurement, as well as ultrafast spectroscopy technology. The results reveal that the twisted additive DPB selectively interacts with acceptor Y6, and thus forms optimized morphology of active layer with increased molecular crystallinity, tight molecular packing, and favorable phase separation. As a result, the optimized devices deliver a remarkable power conversion efficiency (PCE) of 19.04%, which is the highest value for the D18-Cl:N3 system to date. These results demonstrate that non-halogenated and twisted solid additive DPB has broad prospects in the preparation of highly efficient OSCs, providing theoretical and experimental guidance for the development of high-performance solid additives.